This invention relates to a method and apparatus for measuring the shape, size, etc., of a rotary tool, such as a ball end mill and twist drill, and in particular to a method and apparatus for measuring the shape, size, etc., of such a rotary tool with the use of a line sensor.
A ball end mill is employed as a cutting type rotary tool to machine the surface of a work in three-dimensional fashion. As shown in FIGS. 3 and 4, this type of tool 1 has a cutting edge on the outer periphery of straight section 2 and on forward end 3. In the conventional profiling operation, while the surface of a model is profiled by a stylus, the surface of a work is removed by tool 1 to have the same configuration of the model.
A cutting method has already been established which removes a work by moving a tool, under numerical control, such as on a CAD/CAM (computer-aided design/computer-aided manufacture) basis, in a three-dimensional fashion.
In order to remove the work, by a tool, with high precision, the tool per se needs to have an accurate shape and size. In tool 1, such as a ball end mill in particular, whose end is hemispherical in configuration, that hemispherical section 3 should be maintained accurate in terms of its true roundness and its radius. It is thus important to measure tool 1 accurately. It is fairly difficult to accurately measure the dimension of tool 1, since the cutting edge is present on the surface of tool 1.
In the present state, the following methods have been employed in the measurement of the tool.